The invention concerns an identification circuit having an input terminal and an output terminal as well as a memory element to store an identification code, and comprising a counter for counting pulses on the input terminal and a comparator for comparing the identification code and the value of the counter.
The invention is particularly related to an electronic board on which there may be placed a plurality of different marking elements in many different points of a matrix of serial buses. For this use, at least some of the marking elements must contain an electronic identification circuit so that it is possible to register the position of the marking element and its associated identification code.
The British Patent Specification No. 1 365 838 discloses a principle for identification of the number (or priority) of a data unit. This known art is expensive to implement and is not useful in connection with the above-mentioned positional determination.
In connection with a board of the above-mentioned type it is important that the marking elements, which contain an identification circuit and are usually present in a large number, are inexpensive, but on the other hand it is desirable that a minor number of marking elements can perform complicated data processing operations.
The object of the invention is accordingly to provide an identification circuit which is useful in a simple version both for the mentioned positional determination and identification determination but which can also be expanded to handle more complicated data tramsmissions.